1. Field of the Invention
The present invention relates to a transport control system with linear motor drive wherein a carrier having a rotor plate as a secondary conductor is driven along a rail-path having a plurality of stator portions upon energization of the stator portions and, more particularly, to a transport control system with linear motor drive wherein a control function is provided in each stator portion having the corresponding stator. The system according to the present invention is used for cash transportation in a bank or the like.
2. Description of the Related Art
As a transport means, the linear motor car system has attracted a great deal of attention, since high-speed transportation can be achieved thereby without the need to mount a power source in the carrier. In a conventional linear motor car system, a plurality of stator portions are coupled to a rail-path, and a rotor plate is mounted in a carrier. An electric force is supplied to the rotor plate by energizing the corresponding stator portion, thereby driving the carrier. When the stator portion is deenergized, the carrier is stopped. Therefore, once the carrier receives the driving force from a given stator portion, it needs no additional external force and will run freely until reaching the next stator portion. At a carrier stoppage position, the carrier is stopped by a reverse driving force output from the corresponding stator portion.
In such a linear motor car system, the carrier itself need not include a power source but is driven only by energization of the stator portions coupled to the rail-path. Therefore, the carrier can be moved at a high speed and can be made compact in size, thereby minimizing the overall dimensions of the transport system and making it particularly suitable for document transportation in an office, or the like.
In a conventional linear motor car system, the respective stator portions coupled along the rail-path are sequentially energized/deenergized by a linear motor controller when the carrier is running. Thus, the carrier is started, accelerated, decelerated or stopped and is driven from a desired stator portion to another desired stator portion. The linear motor controller controls the respective stators in accordance with the running state of the carrier in such a manner that when the carrier passes through a stator portion, it is controlled to run at a predetermined speed or it is stopped.
In a conventional transport control system wherein a carrier is driven along a rail-path having stator portions, a system controller (microprocessor) supplies running instructions to a linear motor controller (microprocessor) in accordance with running requests from associated equipment (e.g., an autocashier). The linear motor controller controls the stators arranged in stator portions along the rail-path for driving the carrier. The carrier is started from a start position (a given stator portion), is accelerated or decelerated to pass through subsequent stator portions, and is stopped at a desired stop position (another given stator portion). In such a conventional control system, the linear motor controller must always detect an operating status of each stator portion and directly control the stator in such a manner that the carrier is running at a desired speed at the corresponding stator portion. This condition means that the linear motor controller alone receives and processes a plurality of status signals from the respective stator portions, and thus the processing capacity is limited.
When the number of stator portions is small, this limitation will not cause any significant problems. However, when the number of stator portions is increased or the distance between each two adjacent stator portions is very short, the processing capacity of the linear motor controller cannot cope with the actual number of processing requests. To overcome this obstacle, the carrier must be driven at a low speed, which causes some inconvenience. Also, when a system layout is changed, the processing contents of the linear motor controller must be updated, and the operation becomes complicated. In addition, since the processing capacity is limited, processing a malfunction or failure is likewise limited, and during an operation failure, control of the carrier may be interrupted, with the result that business operations are temporarily halted.